The operation and efficiency of batteries (e.g., lead acid batteries) involves many complex electrochemical reactions. Lead acid batteries, including but not limited to valve regulated lead acid (“VRLA”), gelled electrolyte and flooded batteries, are particularly complex. One complication is the generation of oxygen and hydrogen that occurs at the positive and negative electrodes, respectively, when the battery is charged. The ability to prevent excessive oxygen and hydrogen formation within the battery is an aspect of battery design and manufacture that influences the overall quality and operation of a battery.
Further complicating battery recharging is a charge imbalance that builds up between the negative plate(s) and the positive plate(s). This charge imbalance occurs because the battery is charged to a constant voltage where the sum of the voltage elevation or polarization determine when the capped voltage or voltage lid is achieved. When the voltage lid is achieved, the current is reduced by the charging system. The escalation of voltage of one electrode can cause the voltage lid to be reached with subsequent tapering of current before the other electrode is completely charged. The negative electrode in the lead acid battery has high potential for this to happen since the negative plate is significantly more efficient in charging than the positive plate.
As a result of the imbalance, the negative plate obtains a full charge first, after which hydrogen gas production begins. The positive plate continues to charge, albeit more slowly while hydrogen gas is produced. The underlying charge imbalance is difficult to address in current battery designs because the current applied to the battery cannot be regulated to suit the behaviors of the two plates.